In general there is a long felt need for a system and method to identify and locate the exact location of the source of gunfire and a shooter's identity, particularly in a military or urban setting. In many large cities, gun related violence has become a plague of epidemic proportions. It is estimated that roughly 10,000 Americans die each year from gun related injuries, and over 200,000 are non-mortally injured by gunfire. Recent events such as the urban warfare in Iraq and the so-called “Suburban Sniper” in the Washington D.C. area have further underscored the need for a system that can accurately identify and locate the source of gunfire and provide evidence as to the identity of the shooter. Unfortunately many of the prior art devices are inadequate to locate and identify the source of gunfire or shooter in any meaningful way, lack portability necessary for military operations, and are too costly to gain acceptance by communities or the military as a tool to combat crime and aid in warfare, respectively.
In a typical gunshot locating system, a plurality of sensors are situated in the field, usually at regular intervals, along an x-y grid. Each sensor includes a microphone and typically, an amplifier, to produce an audio signal. The audio signal is then carried by a dedicated telephone line to a central location where the sound is processed. Upon detecting a gunshot from the processed audio, relative times of arrivals at the central location are processed to determine a location of the source of the gunshot. These types of gunshot locating systems are described in U.S. Pat. No. 5,973,998 to Showen et al. and U.S. Pat. No. 6,552,963 to Baranek et al.
Showen et al. teaches a gunshot locating system that employs sensors, e.g. microphones, which are permanently placed at a density of roughly six to ten sensors per square mile. Each of these sensors requires a dedicated phone line to transmit sound data to a central data processing center for signal processing. The central data processing center determines whether a gunshot has been fired and the location of the gunshot. Similarly, Baranek et al. discloses a gunshot locating system that is essentially a hard wired alarm system. The alarm system includes a gunshot detector comprising a transducer for detecting sound that is connected to an amplifier, a signal filter and to a transceiver for communicating with a central data processing center. However, neither Showen et al. nor Baranek et al. teach a method of processing acoustical gunshot data to determine the type of weapon used to fire the gunshot and using a video camera and video signals to locate a shooter. Furthermore, neither Showen et al nor Baranek et al. teach a gunshot locating system that is portable.
U.S. Pat. No. 6,847,587 to Patterson et al. teaches a gunshot location device that also includes a microphone, a processor for discriminating between acoustic events, a synchronized clock, and an interface for communicating with a network. However, Patterson et al improved upon the systems of Showen et al and Barank et al. by providing an array of sensors that both located the source of the gunshot and also compared the acquired data with sound data to determine the weapon used. But, the system of Patterson still lacks the portability required to make a gunshot location device practical in military operations, and the system doesn't offer any mechanism for correcting signal processing errors, e.g., false positive gunshot signals or inaccurate weapon determinations.
Therefore, a gunshot locating system that is small enough to be portable and can accurately identify the source of the gunshot is a much needed improvement over the art.